2003 ls 3.9 no heat

10-12-2016, 11:36 PM
Ive looked everywhere and cant seem to get a good answer on my issue with my 03 ls. it has no heat ac works great. ive got no heat to heater core from the control valve.( all 3 of the hoses are cool to the touch but a hose below thos is hot but im not sure where it comes from) I put in a new thermostat and still no change. car does not overheat it runs normal operating temps all the time. the top radiator hose is hot but from the thermostat hose down its warm just on the elbow right after the thermostat but the rest is not even warm.

im needing some ideas and ways to test so im not throwing money on parts it doesn't need.

12-31-2016, 09:49 AM
I am also having a problem with no heat.I bought the car and it was overheating.Looked up instruction to bled sysstem.When I did a transparent jelly type substance came out of heater bleed valve.It stopped overheating but the hose to the thermostat would not stay on.Replaced thermostat housing and engine fill with a aluminum one for the plastic one was brittle and breaking off.Put new thermostate in.And repeated the purge process.Now thinking it is all fixed I jumped into the car and drove down the street heat stayed normal,but no heat from dash on either side,just cold air.Can anyone tell me where to start it is freezing outside and I have two babies that have to sit in this car for appointments.Thank you.

12-31-2016, 04:54 PM
...drove down the street heat stayed normal,but no heat from dash on either side,just cold air.

I'm confused by the quoted statement. When you said "heat stayed normal" were you referring to the engine temperature versus the interior heat temperature? Is your LS also a V8? I'm kind of surprised no one (myself included) replied to the original post. Based on his diagnosis of of the tube temperatures at the DCCV, it sounds like the DCCV is stuck closed on his car. If you're able to perform a similar diagnosis with a similar result, your DCCV may be stuck as well. It's a pretty common issue and there are several threads on this forum describing the issue, where the DCCV is located, and how to replace. -Rod

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